1. Field of the Invention
The present invention relates to an electrical discharge machining apparatus, and more particularly to an electrical discharge machining apparatus wherein, with slight modification of the CNC controller, the workhead can serve not only for the processing of a workpiece, but additionally can perform the changing out of the electrode and work-piece carrying pallet. The invention makes possible the dispensing of the conventionally required robot.
2. Description of the Related Art
An electrical discharge machining apparatus is used in the processing of work pieces, which are mounted on pallets. For this, a workhead is mounted on guideways and is displaceable in all three coordinate directions, that is, in the X-, Y- and Z-directions, by means of a computer numerical control (CNC)-controller. Below the workhead there is to be found a work area, which is essentially defined by a setup plate. On the setup plate an automatic chuck is provided, which secures the pallet with its thereupon mounted workpieces during the work processing. The setup plate inclusive of the chuck is situated in a container, which contains the dielectric. The respective sub-elements of the electrical discharge machining apparatus are received on a machine bed, in which a filter device for the dielectric is also integrated.
With the help of the CNC controller it is possible to convey an exchangeable electrode, which is mountable on the workhead or, as the case may be, the spindle, exactly into position with respect to the workpiece to be processed. The delivery and removal of the workpiece pallets and the electrodes occurs by means of a robot, which is provided next to the electrical discharge machining apparatus. The robot can, by means of a gripper mounted on a gripper arm, on the one hand, grasp an electrode which is available from a magazine and bring this to the workhead. For this an automatic chuck is provided on the workhead, so that the electrode is grasped and held. On the other hand, the robot services a further magazine, in which workpiece-covered pallets are supplied. The gripper grabs this pallet and brings this to the work area. There the pallet is secured by means of an automatic chuck. During the work processing process, the gripper arm of the robot is removed from the work area and the workhead erodes the desired contour according to the control program.
The disadvantage of this type of electrical discharge machining apparatus is comprised therein, that it is very expensive. This concerns not only the electrical discharge machining apparatus itself, but rather in particular the networking with the robot, which accomplishes the necessary delivery and removal of electrodes and pallets.